Snap action switch assembly

ABSTRACT

A snap action electrical switch assembly including a support housing. The support housing includes a movable contact means comprising a metal cantilevered resilient lever with a contact element disposed on the distal end thereof and movable between two spaced fixed contacts. A control member is snapped into rotary engagement with the support housing and extends along and engages opposite sides of the resilient lever intermediate the ends thereof. A projection extends downwardly from the control member and engages a groove in a rotary cam. A biasing member is snapped onto and is rotatably supported on the control member and includes a forwardly extending portion having a projection engaging the groove in the rotary cam. The biasing member also includes parallel arms on each side of the control member for biasing the resilient lever in opposite directions so that as the cam rotates the biasing member moves between opposite positions biasing the resilient lever in one of two opposite directions before the cam allows the control member to rotate at which time the resilient lever will be allowed to move the contact element into or out of engagement with one or the other of the fixed contacts.

Unite States atet 1 Tucker et al.

[ Mar. 27, 1973 [54] SNAP ACTION SWITCH ASSEMBLY [75] Inventors: ThomasM. Tucker, Royal Oak; Edwin F. Clemett, Jr., Detroit, both of Mich.

[73] Assignee: McCord Corporation, Detroit,

Mich.

[22] Filed: July 1,1971

[211 App]. No.: 158,917

[52] U.S. Cl; ..200/78 [51] Int. Cl ..HOlh 15/18 [58] Field of Search..200/153 L, 153 LB, 77, 78

[56] References Cited UNITED STATES PATENTS 2,335,110 11/1943 Dann..200/78 3,402,275 9/1968 Podgorski et al. ..200/153 L 1,114,225 10/1914Cahusal ..200/153 LB [57] ABSTRACT A snap action electrical switchassembly including a support housing. The support housing includes amovable contact means comprising a metal cantilevered resilient leverwith a contact element disposed on the distal end thereof and movablebetween two spaced fixed contacts. A control member is snapped intorotary engagement with the support housing and extends along and engagesopposite sides of the resilient lever intermediate the ends thereof. Aprojection extends downwardly from the control member and engages agroove in a rotary cam. A biasing member is snapped onto and isrotatably supported on the control member and includes a forwardlyextending portion having a projection engaging the groove in the rotarycam. The biasing member also includes parallel arms on each side of thecontrol member for biasing the resilient lever in opposite directions sothat as the cam rotates the biasing member moves between oppositepositions biasing the resilient lever in one of two opposite directionsbefore the cam allows the control member to rotate at which time theresilient lever will be allowed to move the contact element .into or outof engagement with one or the other of the fixed contacts.

15 Claims, 6 Drawing Figures PATENTEUmznz-m ,7 3,5 3

sum 1 OF 2 v 55 r y 4 JIHJIlLf W 5 INVENTOR.

ATTORNEY PATENT 3,723,683

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ATTORNEY SNAP ACTION SWITCH ASSEMBLY This invention relates to a snapaction electrical switch.

Snap action electrical switch assemblies are well known in the art andhave as their purpose the function of snapping electrical contacts intoand out of engagement with one another to prevent sparking therebetweenthereby prolonging the life of the contacts of the switch.

It is an object and feature of this invention to provide a snap actionelectrical switch assembly having improved characteristics over thoseknown in the prior art.

In correlation with the foregoing object and feature, it is anotherobject and feature to provide a snap action switch including biasingmeans movable between opposite biasing positions by the cam means forbiasing the contacts of the switch into and out of engagement with oneanother, the cam means allowing movement of the contacts relative to oneanother only after the biasing force is applied.

In correlation with the foregoing objects and features, it is anotherobject and feature of this invention to provide a snap action electricalswitch which includes biasing means for biasing a movable contact meansinto engagement with a fixed contact means when in a first position andfor biasing the movable contact means out of such engagement when in asecond position and cam means operable with the movable contact meansand the biasing means for moving the biasing means to the first positionand subsequently allowing movement of the movable contact means out ofengagement with the fixed contact means and for moving the biasing meansto the second position and subsequently allowing the movement of themovable contact means into engagement with the fixed contact meanswhereby the movable contact means snaps into and out of engagement withthe fixed contact means.

In correlation with the foregoing objects and features, it is anotherobject and feature of this invention to provide such a snap actionelectrical switch assembly wherein the movable contact means may moveinto and out of engagement with multiple fixed contact means.

In correlation with the foregoing objects and features, it is anotherobject and feature of this invention to provide an improved snap actionelectrical switch assembly wherein the position of the movable contactmeans is highly flexible and only depends upon the cam means.

Other objects and attendant advantages of the present invention will bereadily appreciated as the same becomes better understood by referenceto the following detailed description when considered in connection withthe accompanying drawings wherein:

FIG. 1 is a fragmentary plan view of a preferred embodiment of theinstant invention;

- FIG. 2 is a cross sectional view taken substantially along line 2-2 ofFIG. 1;

FIG. 3 is a view taken substantially along line 3-3 of FIG. 2;

FIG. 4 is a fragmentary cross sectional view taken substantially alongline 4-4 of FIG. 2;

FIG. 5 is a fragmentary cross sectional view taken substantially alongline 5-5 of FIG. 2; and

FIG. 6 is a cross sectional view taken substantially along line 6--6 ofFIG. 2. 1

Referring now to the drawings, a snap action electrical switch assemblyconstructed in accordance with the instant invention is generally shownat 10.

The assembly includes a plastic support housing generally indicated at12.

The housing supports at least one and, as shown, two fixed contactmeans, each of which is generally indicated at 14. Each fixed contactmeans 14 includes a metal plate-like member attached to the supporthousing 12 with a contact element secured to the lower end thereof. Eachplate is attached to the housing 12 by tabs 16 and 18.

The assembly 10 also includes movable contact means including aresilient metal lever 20 which is secured to the housing 12 at one endand extends to a distal end where a contact element 22 is supported. Thelever 20 is secured to a plate-like member 24 by rivets 26 and theplate-like member 24 is secured to the housing 12 in a manner similar tothe plate-like members making up the fixed contacts 14.

The assembly 10 also includes biasing means generally indicated at 28for biasing the lever 20 and hence the contact element 22 intoengagement with one of the fixed contact means when in a first positionand for biasing the lever 20 and hence the element 22 out of engagementwith the same fixed contact means when in a second position. As willbecome more clear as the description proceeds, the movable contactelement 22 may be moved between the two fixed contacts or may be movedand held in a position between the fixed contacts.

The assembly 10 also includes cam means generally indicated at 30cooperable with the movable contact means and the biasing means 28 formoving the biasing means 28 to the first position and subsequentlyallowing movement of the movable contact means into engagement with oneof the fixed contact means and for moving the biasing means to a secondposition and subsequently allowing movement of the movable contact meansout of such engagement. The movable contact means snaps into and out ofsuch engagement.

More specifically, there is included control means comprising the membergenerally indicated at 32 operable between the lever 20 and the cammeans 30 for controlling the position of the lever 20 and the contactelement 22. The control member 32 is rotatably supported by the supporthousing 12 for rotation relative thereto about an axis A. The axis A isspaced from the connection of the lever 20 to the plate 24 and thus tothe housing 12. The lever 20 extends from its connection to the housingin a direction radially away from the axis A.

The control means 32 comprises a control member having a shaft 34 whichis snapped into rotatable engagement with the housing 12. The controlmember 32 extends from the shaft 34 along and in parallel relationshipto and beneath the lever 20 and includes upstanding abutments 36 whichengage the lever 20 on opposite sides thereof intermediate the ends ofthe lever 20. The shaft 34 also has a lower portion onto which thebiasing means 28 is snapped and supported for rotational motion. Thebiasing means or member 28 includes first and second resilient arms 38and 40. The

arms 38 and 40 are disposed on opposite sides of the lever 20 forbiasing the lever 20 in opposite directions depending-upon the positionof the biasing means 28. More specifically, the arms 38 and 40 havebearing portions 42 which engage opposite sides of the control member 32so as to bias the resilient lever 20 in opposite directions by actingthrough the control member 32. The biasing member 28 has a semi-circularupwardly extending flange 42 at the rear thereof and is snapped onto thelower portion of the shaft 34 of the control member 32 for rotationrelative thereto and relative to the housing 12 about the axis A. Thebiasing member 28 also includes a leg 46 extending forwardly from theaxis A and terminating in a projection 48. The biasing member 28 alsoincludes a strengthening rib S0. The projection 48 is cooperable withthe cam means 30 for moving the biasing member 28 between selectedpositions.

Another projection 52 extends from the control member 32 in theproximity of the abutments 36 which engage the lever 20 and in adirection transverse to and away from the lever 20. Thus, the cam means30 is cooperable with the projections 48 and 52 for controlling movementof the control member 32 and the biasing member 28.

The cam means 30 comprises a rotary cam member including a cam trackdefined by a groove 54 for coacting with the projections 48 and 52. i

It will be clear to those skilled in the art that although the assemblyillustrated in this application includes two fixed contacts with whichthe movablecontact element 22 may cooperate, the basic invention needonly employ one fixed contact element cooperable with the movablecontact 22. Thus, in describing and claiming the instant inventionreference is made to one movable contact which is movable into ancl outof engagement with only one fixed contact.

In describing the operation of the assembly, reference will be made toonly one fixed contact and the movable contact element 22 being movedinto and out of engagement with that fixed contact, the fixed contactbeing the upper fixed contact as shown in FIG. 3 or the fixed contactwhich is shown in FIG. 2. The rotary cam rotates in the directionindicated in FIGS. 2 and 6 and upon so rotating the shoulder 56 willmove the projection 48 of the biasing member 28 so as to urge the arm 40thereof into engagement with the control member 32 thus urging thecontrol member 32 to move the lever 20 toward the upper fixed contact16. The projection 52, however, remains in the track 54 and is preventedfrom allowing the control member 32 to rotate, thus holding the lever 20in a position where the movable contact 22 is in the neutral position.out of contact with the upper fixed contact 16 or in contact with thelower fixed contact depending upon the configuration of the cam track.As the cam 30 continues to rotate, however, the projection 52 will bedisposed in a position where it is free to move laterally, thus allowingthe control member 32 to rotate. The control member 32 and the lever 20will be moved very rapidly under the biasing action of the arm 40, thussnapping the movable contact 22 into engagement with the upper fixedcontact 16 shown in FIG. 3.

In reversing the action, the projection 48 will move .back into thetrack 54 thus moving the arm 38 into engagement with the control member32 thereby urging the control member 32 to rotate in the oppositedirection. The control member 32, however, is prevented from rotating inthe opposite direction because the projection 52 thereof is disposed inthe offset portion 58 of the cam track 54. When the projection 52reaches the end of the offset portion 58, it is free to move back intothe track 54 thus snapping the movable contact element 52 out ofengagement with the upper fixed contact 16.

It will be understood by those skilled in the art that the second orlower fixed contact 16 is engaged by the movable contact 22 by theaction of the biasing member 28 and under the control of the cam meansin the same manner as it is movable into and out of engagement with theupper fixed contact means as described above. It will be furtherunderstood by those skilled in the art that the movement of the movablecontact 22 is totally the function of the configuration of.

the cam track 54 which may be of various different configurations. Itwill be further understood by those skilled in the art that variousdifferent cams may be utilized instead of the rotary cam shown,including cams utilizing plural tracks, i.e., a separate track for eachof the projections 48 and 52.

The invention has been described in an illustrative manner, and it is tobe understood that the terminology which has been used is intended to bein the nature of words of description rather than of limitation.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. It is, therefore, to beunderstood that within the scope of the appended claims, the inventionmay be practiced otherwise than as specifically described.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows;

1. A snap action electrical switch assembly comprising: at least onefixed contact means, movable contact means, biasing means for directlybiasing said movable contact means toward engagement with said fixedcontact means when in a first position and for biasing said movablecontact means away from engagement when in a second position, and cammeans cooperable with said movable contact means and said biasing meansfor moving said biasing means to said first position and subsequentlyallowing movement of said movable contact means into engagement withsaid fixed contact means and for moving said biasing means to saidsecond position and subsequently allowing movement of said movablecontact means out of engagement with said fixed contact means so thatsaid movable contact means snaps into and out of engagement'with saidfixed contact means.

2. An assembly. as set forth in claim 1 including in addition to saidfirst mentioned fixed contact means a second fixed contact means, saidmovable contact means being movable into and out of engagement with saidsecond contact means by said biasing means under the control of said cammeans in the same manner as it is movable into and out of engagementwith said first fixed contact means.

3. An assembly as set forth in claim 1 including a support housing, andwherein said movable contact means includes a resilient lever secured tosaid housing and extending to a distal end, a contact element secured tosaid distal end, and control means cooperable between said lever andsaid cam means for controlling the position of said lever and saidcontact element.

4. An assembly as set forth in claim 3 wherein said biasing meansincludes positioning means cooperable with said cam means for movingsaid biasing means between said first and second positions.

5. An assembly as set forth in claim 4 wherein said biasing meansincludes first and second resilient arms disposed on opposite sides ofsaid lever for biasing said lever in opposite directions depending uponthe position of said biasing means.

6. An assembly as set forth in claim 5 wherein said control means isrotatably supported by said support housing for rotation relativethereto about an axis.

7. An assembly as set forth in claim 6 wherein said biasing means isrotatably supported on said housing for rotation about said axis.

8. An assembly as set forth in claim 7 wherein said axis is spaced fromthe connection of said lever to said housing, and said lever extendsfrom its connection to said housing in a direction away from said axis,said control means includes a control member extending from said axisalong said lever and engages said lever on opposite sides thereofintermediate the ends of said lever.

9. An assembly as set forth in claim 8 wherein said resilient arms ofsaid biasing means engage opposite sides of said control member wherebysaid cam means may rotate said biasing means to said first positionwhere a first of said arms acts through said control member to urge saidlever in a direction to engage said contact element with said fixedcontact meansbefore allowing said control member to rotate so that uponallowing said control member to rotate said contact element snaps intoengagement with said fixed contact means and said cam means may rotatesaid biasing means to said second position where the second of said armsacts through said control member to urge said lever in the oppositedirection before allowing said control member to rotate so that uponallowing said control member to rotate said contact element snaps out ofengagement with said fixed contact means.

10. An assembly as set forth in claim 9 including a first projectionextending from said control member in the proximity of the position inwhich said control member engages said lever and in a directiontransverse to and away from said lever, and wherein said biasing meansincludes a leg extending from said axis toward said first projection andterminates in a second projection, said cam means being cooperable withsaid projections for controlling movement of said control member andsaid biasing means.

11. An assembly as set forth in claim 10 wherein said control memberincludes a shaft one end of which is snapped into rotary engagement withsaid housing, said positioning means being snapped onto the other end ofsaid shaft to be rotatably supported thereby.

12. An assembly as set forth in claim 10 including in addition to saidfirst mentioned contact means a second fixed contact means, said movablecontact element being movable into and out of engagement with saidsecond contact means by said biasing means under the control of said cammeans in the same manner as it is movable into and out of engagementwith said fixed contact means.

13. An assembly as set forth in claim 10 wherein said cam means includesat least one cam track for coacting with said projections.

14. A snap action switch assembly comprising; at least one fixed contactmeans, movable contact means, biasing means movable between first andsecond positions for directly biasing said contact means toward and awayfrom engagement with one another, and cam means cooperable with saidbiasing means and said contact means for allowing relative movementbetween said contact means only after the biasing force is applied bysaid biasing means.

15. A snap action electrical'switch assembly comprising: at least onefixed contact means, moveable contact means, biasing means for directlybiasing said moveable contact means toward and away from said fixedcontact means, and control means coacting with said biasing means andsaid moveable contact means for initially restraining said moveablecontact means and subsequently allowing snap action closure orseparation of said electrical contacts after said biasing means appliesabiasing force to said moveable contact means.

1. A snap action electrical switch assembly comprising: at least one fixed contact means, movable contact means, biasing means for directly biasing said movable contact means toward engagement with said fixed contact means when in a first position and for biasing said movable contact means away from engagement when in a second position, and cam means cooperable with said movable contact means and said biasing means for moving said biasing means to said first position and subsequently allowing movement of said movable contact means into engagement with said fixed contact means and for moving said biasing means to said second position and subsequently allowing movement of said movable contact means out of engagement with said fixed contact means so that said movable contact means snaps into and out of engagement with said fixed contact means.
 2. An assembly as set forth in claim 1 including in addition to said first mentioned fixed contact means a second fixed contact means, said movable contact means being movable into and out of engagement with said second contact means by said biasing means under the control of said cam means in the same manner as it is movable into and out of engagement with said first fixed contact means.
 3. An assembly as set forth in claim 1 including a support housing, and wherein said movable contact means includes a resilient lever secured to said housing and extending to a distal end, a contact element secured to said distal end, and control means cooperable between said lever and said cam means for controlling the position of said lever and said contact element.
 4. An assembly as set forth in claim 3 wherein said biasing means includes positioning means cooperable with said cam means for moving said biasing means between said first and second positions.
 5. An assembly as set forth in claim 4 wherein said biasing means includes first and second resilient arms disposed on opposite sides of said lever for biasing said lever in opposite directions depending upon the position of said biasing means.
 6. An assembly as set forth in claim 5 wherein said control means is rotatably supported by said support housing for rotation relative thereto about an axis.
 7. An assembly as set forth in claim 6 wherein said biasing means is rotatably supported on said housing for rotation about said axis.
 8. An assembly as set forth in claim 7 wherein said axis is spaced from the connection of said lever to said housing, and said lever extends from its connection to said housing in a direction away from said axis, said control means includes a control member extending from said axis along said lever and engages said lever on opposite sides thereof intermediate the ends of said lever.
 9. An assembly as set forth in claim 8 wherein said resilient arms of said biAsing means engage opposite sides of said control member whereby said cam means may rotate said biasing means to said first position where a first of said arms acts through said control member to urge said lever in a direction to engage said contact element with said fixed contact means before allowing said control member to rotate so that upon allowing said control member to rotate said contact element snaps into engagement with said fixed contact means and said cam means may rotate said biasing means to said second position where the second of said arms acts through said control member to urge said lever in the opposite direction before allowing said control member to rotate so that upon allowing said control member to rotate said contact element snaps out of engagement with said fixed contact means.
 10. An assembly as set forth in claim 9 including a first projection extending from said control member in the proximity of the position in which said control member engages said lever and in a direction transverse to and away from said lever, and wherein said biasing means includes a leg extending from said axis toward said first projection and terminates in a second projection, said cam means being cooperable with said projections for controlling movement of said control member and said biasing means.
 11. An assembly as set forth in claim 10 wherein said control member includes a shaft one end of which is snapped into rotary engagement with said housing, said positioning means being snapped onto the other end of said shaft to be rotatably supported thereby.
 12. An assembly as set forth in claim 10 including in addition to said first mentioned contact means a second fixed contact means, said movable contact element being movable into and out of engagement with said second contact means by said biasing means under the control of said cam means in the same manner as it is movable into and out of engagement with said fixed contact means.
 13. An assembly as set forth in claim 10 wherein said cam means includes at least one cam track for coacting with said projections.
 14. A snap action switch assembly comprising; at least one fixed contact means, movable contact means, biasing means movable between first and second positions for directly biasing said contact means toward and away from engagement with one another, and cam means cooperable with said biasing means and said contact means for allowing relative movement between said contact means only after the biasing force is applied by said biasing means.
 15. A snap action electrical switch assembly comprising: at least one fixed contact means, moveable contact means, biasing means for directly biasing said moveable contact means toward and away from said fixed contact means, and control means coacting with said biasing means and said moveable contact means for initially restraining said moveable contact means and subsequently allowing snap action closure or separation of said electrical contacts after said biasing means applies a biasing force to said moveable contact means. 